Combined Tibial Tubercle Osteotomy and Medial Patellofemoral Ligament Reconstruction for Recurrent Lateral Patellar Instability in Patients With Multiple Anatomic Risk Factors

Abstract

Purpose: To report the outcomes for combined tibial tubercle osteotomy (TTO) and medial patellofemoral ligament (MPFL) reconstruction and assess for potential risk factors for recurrent instability and/or poor outcomes.

Methods: The medical record at our institution was reviewed for patients treated with MPFL reconstruction and TTO for recurrent lateral patellar instability from 1998 to 2014. Preoperative imaging was assessed for trochlear dysplasia according to the Dejour classification (high grade = B, C, D) and the presence of patella alta using the Caton-Deschamps ratio (>1.2). The indication for combined MPFL reconstruction and TTO was MPFL insufficiency and a lateralized tibial tubercle. Outcomes were determined by recurrent instability, return to sport, and Kujala and International Knee Documentation Committee (IKDC) scores.

Results: Thirty knees in 28 patients (14 M, 14 F) with a mean age of 22.6 ± 9.1 years (range, 13-51 years) were included with a mean follow-up of 48 ± 28 months (24-123 months). Seventy-three percent (22/30) had high-grade trochlear dysplasia, and 63% (19/30) had patella alta. One patient had a postoperative dislocation and 1 had a subluxation event. The Caton-Deschamps ratio decreased by a mean of 0.2 (P = .001), leaving 30% with postoperative patella alta. The mean postoperative scores were as follows: Tegner = 5 ± 2, Kujala = 89 ± 16 (45-100), and IKDC = 85 ± 17 (44-100). Eighty-three percent (15/18) returned to their preoperative sport. Female gender was a risk factor for lower IKDC (77.3 vs. 92.6, P = .01) and Kujala (82.2 vs. 95.0, P = .03) scores. Medialization greater than 10 mm was directly correlated to lower IKDC (P = .02) and Kujala (P = .01) scores.

Conclusions: The combination of MPFL reconstruction and TTO in patients with trochlear dysplasia results in low recurrence of instability. Patients on average had good subjective outcomes and were able to return to sport. Female gender and tibial tubercle medialization greater than 10 mm were associated with worse outcomes.

Level of evidence: Level IV, therapeutic case series.